A. Technical Field
The present invention relates to a cargo container with an insulated floor. In one embodiment, the cargo container is a railroad boxcar.
B. Related Art
Currently, many shippers utilize refrigerated and/or insulated large cargo containers (such as boxcars) to transport items that require the maintenance of specified temperatures during transit. Because these containers are required to maintain certain temperatures, the thermal efficiency of these containers is an important feature. Thermal efficiency is characterized by the thermal conductivity of a particular component or its inverse, its resistance to heat transfer, commonly referred to as an R-value.
In these containers, a significant amount of heat loss occurs through the floor or other places with thermal shorts. A typical container floor is constructed of metal, which is highly conductive to heat transfer. Since the underside of the floor is exposed to ambient conditions, the conductive properties of the metal floor cause heat loss through the floor and decrease the thermal efficiency of the cargo container. In addition, the floor typically has a series of structural members located on the under surface of the floor, which are also constructed of metal. These structural members also contribute to the heat loss through the floor and further decrease the thermal efficiency of the cargo container.
Therefore, there is a need for an insulated floor for a cargo container with increased thermal efficiency.